Pier-door



L. MCHARG. PIER DOOR.

APPLICATION FILED JUNE l5, |920.

Patented Fel 22, 1921.

2 SHEETS-SHEET l.'

Jig-2f Be it known that I,..LEsL1n citizen of the United'4 States, residingfat Freeport, in the' county of Nassau,.State or'v New ,-York, have invented: certain new and. l useful Improvements in'` Pier-Doors, .of ,which .the-,following isa full, clear, andaccompanying drawings', in which:

' -IUNITEDg ATES;

PATENT OFFICE.A

i 1 A'LESLIE manana, or FREnPoRnNEw Yonx.

Hna-Doon.

To all edwin. may camera: i MCHARG, a

exact description The invention forming the subject of this 1o.' application forI Letters Patent isan improvement in doors vfor pier. sheds, lfreight warehouses and the like',l and which are composed-ofjtwo sections adapted to slide ver-f tically'until one overlaps the other and then to move laterally-until the two sections lie lin a substantially horizontal position.

` Doors of this generalcharacterare very' widely used. The fact that they are necessarily'somewhat massive and of considerable 4'weight' makes their ready and easy operation diiicult and the means for' such operation expensive andcomplicated,` whichobjections I have sought to and have succeeded inover-v comingv by the construction that character- According tommy. inventlon I employ two yverticallyl slidingsections, -counterbalanced by .a weight 'equal'to both, but arranged move at one-half of the speed of the -ri'sing lower sectionand at the 'same speed as the.

. two overlapping sections, so that no greater -power is required tolift one section than the two. I also apply the counterbalancing".

weight in such manner that eitherfor both conditions, such as' fricj My improvements" .ary-illustrated the Figu ted lines.

Fig. 2 is a top plan'lview ofthe same, parts? of the framework' being indicated in dotted V'lines. V

Figs. 4, 5, e and 7 are lia-.aug f a' leaning tions.

l mounted above the two .tionfi's not moved a .f nections shown and. described the counterbalance weights movedownward but at one` half lthenspeed at whichfthe lower door section moves u This continues 'until the' rounded and downward rollers 18 secured to brackets 19 on theu per part of the u l guideway's.

re lis a view in side elevation of the- .45 door, the framework being indlcatedby dot;-

' Specification of Letters Patent. e Patented Feb.v 22, 1921-. v s -f Application mea Janes, 1920. serial No. ssege'n.

.In main features of. construction and `operation the door 1s similar'to many others of its class and comprises an upper section 1 and alower sectin 2`adapt'ed to slide vertically, the lower section under guide plates 3 secured to .the upper section. A spindle 4.

ing or closing the door,.and the motion of- .thisspr'ocket i's'communicated b y a chain 7y and sprockets' 8 andv8 ofproper' relative diameters to raise the s eed to 'a shaft 9,' oor sections. The

above devices are common in this class of door; ,t

To the middle points 10 on'the side edges of the upper section of the door'are connected sprocket chains 11 which run over weights 14, then up over sheaves 15 secured to shaft`9, and thence to'y the bottom of the .flower section 2 where they are connected to arms orbrzatcketsl.` l i From theconstruction it follows that the cham 6. be pulled to rotate the sprocket to 5,"the vshaft?) is rotated andthe chain 1l pull-ed up raisin the'lower section of the door.` During this raeration the'upper s'ec- .by reason of the con- Llower section ully overlaps the' upper.

Aroot beams, are' two 'lgiideways 17 with y inclined ends, and

pier door; section enter t ese en; therefore, the lower sec tion. fully overlaps the upper, the force Iaplied to thechain v1 1 movesboth upper and ower-sections tgethemfand the top of the upper. section isy carried out laterally and follows the lguide way until the two sections ,lie in a substantially'horizontal' position, or l at .r1ght. angles to theirl former positionv of rest. f During the upward movement of the door sections the counterbalance weightsv mani-l 1'loo los festly nove at twice their former speed, or.

at the samespeed as the'door sections are moving, but Vthe weights 'are 'suilicientto counterba'lance both sections, sov that no Iso tions while the weight .is moving at its fullx rate. It also results from the fact that the chain 11 is connected to the middle points of the upper sectionthat the entire door will be exactly. counterbalanced in all".v positions, e variable portions' of the weight/being car-l ried by the horizontal guides and'by the chains.

' v It may happen that frictional contact between the two door sections or other 'causes will operate to move one section improperly wit-hreference to the other. For example, in opening the door the lifting of thev lower section might start the vupper section in movement which is not wanted, and to prevent this I secure to the top of the upper section a form of lat-cli Ywhich prevents such displacement.

This device `is shown in detailv in Figs. 4f to 7 and consists of two pivoted latches 20 and 21 on pivots 22 'carried on the upper edge of vthe door section. One of these latches Q1 has at the end of one arm a catch 23 which, in' the normal position of the upf A' lap enga-ges with the Stop 25 and locks ,the

lease the lower section which is thereforev free to descend while the upper section re mains stationary. Any other means of-thisr. natui'e might be used to preserve the two -sections under all circumstances in their vproper relative positions.

Innumerable doors of this general Aclass havebeen used or proposed, but my improvement resides in the specific arrangement ofA 'chains or theirA equivalents and the counterweight's, whereby n o more poweris required to raise one section of the; door that both sections, whereby one weight only for each side of` the door is required and whereby both doors are perfectly counterbalanced inall positions.

claims are not essential to the invention and may be greatly varied in construction and iii-some cases omitted.v

lVhat I claim is:

1. In a pier shed door, thecombination with two vertically and horizontally movable sections and ashaft by the rotation of which they are raised and moved laterally on the opening of thedoor, of a sheave fast `tosaid sha-ft and a sheave loose thereon, a 'counterweight equal -to the weight. of both door sections 'carryinga sheave and a chain or its equivalent connected at oneend .to the bottom of the lower door section and at its other to the middle of the upper section and running over the said sheaves as herein set forth.

2.. In a pier shed door,` 'the combination with the door jamb, upper'and lower door sections, and means for guiding the same vertically until they overlap and then laterally until they occupy a horizontal position, of a shaft byv the rotation of which The partsv not specifically defined in the said door' is opened and closed, a sheave xed to said shaft and a shea-ve loose thereon at 'each lside of the door, counterweights equal 4` .to the weight of both doors, sheaves carried thereby, and two chains or their equivalents,

one endl of each `connected tothe bottom of the lower door section and the other to the middle of the upper section and each rminingy over allof the sheaves at one side of the door', as set'forth, 1

3- Iii a pier shed door composed of? vertizcwlily and laterally movable sectionsaid mea-iis for opening and the door,h of

llatches secured to the top, off upper see- 7 Los:

tion, a fixed stop near'the normal; level o. the-top ofthe upper section and a stop at the lripper edge ofthe lower for with the latches, whereby thietw'o sections will always be preserved in their proper and,

normal relative positions. -I

In-testiiony whereof I hereto ailix my signature. i t y LESLIE'MGHARG. 

